<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>分支语句</title>
</head>
<body>
    <script>
        // 单分支语句
        if(100 > 10){
            document.write('成立')
        }
    </script>
    <br>
    <script>
        // 双分支语句

        if(100 < 10){
            document.write('成立')
        }else{
            document.write('不成立')
        }
    </script>
    <script>
        // 多分支语句
        var score = 50
        if(score >=90){
            console.log('A')
        }else if(score >= 80){
            console.log('B')
        }else if(score >= 70){
            console.log('C')  
        }else{
            console.log('D')
        }
        console.log('不及格')
    
    </script>
    
    
</body>
</html>